The present invention relates to a headlamp for automotive use having a discharge bulb as a light source, and more particularly to an automotive headlamp having a lamp body which is coated with a conductive layer effective for shielding the headlamp to prevent electromagnetic waves generated by the discharge lamp and a feeder connected to the discharge lamp from escaping from the headlamp. It is required to prevent such electromagnetic waves from escaping the headlamp since they can interfere with the radio of the vehicle and affect the operation of other electrical units.
FIG. 8 shows a conventional headlamp of the same general type as that to which the invention pertains. In a container-shaped lamp body "a" there is provided a reflector "d" to which a discharge bulb "c" is attached. A front lens "d" is assembled to a front opening of the lamp body "a". In this way, the headlamp is formed as an integral unit. A unit "e" to which a lighting circuit for activating a high voltage on the discharge bulb "c" is assembled is fixed to a rear opening of the lamp body "a". The bulb "c" is connected with this lighting circuit by a connector "f". On the external surface of the lamp body "a", there is provided a conductive layer (conductive coating film) "g" that is an electromagnetic wave shielding film for preventing electromagnetic waves generated by the discharge bulb "c", the feeder of the discharge bulb, and the connector "f" from leaking outside the lamp body "a".
However, as shown in the enlarged view of FIG. 9, the conventional conductive layer described above is composed of a coating film on which metal pieces "h" are dispersed, so that its overall strength (both heat-resistance and anti-thermal shock property) is low, and further the film thickness is not uniform. The electromagnetic wave shielding effect tends to deteriorate in areas where the film thickness is small, that is, the electromagnetic waves can be transmitted through a region in which the film thickness is small. Therefore, the desired effect of shielding the headlamp from electromagnetic waves transmission cannot be completely obtained.